MIMO Power Line Communications

Abstract

International audienceDespite being a well-established ingredient to many wireless systems, multiple input multiple output (MIMO) signal processing has only recently been considered for broadband power line communications (PLC). Adapting multiple-antenna transmission and reception techniques to a wired medium such as the electrical grid requires solving a number of issues, both regarding the physics of electromagnetic transmission and the optimization of the signal processing strategies. In the last few years, significant steps were made to demonstrate the benefits of MIMO PLC and to develop the necessary hardware. As a result, MIMO PLC has been adopted in several broadband PLC specifications, precisely as part of ITU-T G.hn in Recommendation G.9963, and as part of the industry specification HomePlug AV2, which is backward compatible to IEEE 1901. This article reviews important aspects of MIMO PLC, highlighting its similarities and main differences with classical wireless MIMO. It focuses first on the peculiarities of the electrical grid, with a survey of PLC channel and noise characterization in a MIMO context. It further estimates MIMO PLC channel capacity adhering to the electromagnetic compatibility regulations currently in force. Besides, MIMO signal processing techniques most suited to PLC environments are discussed, allowing for throughput predictions. It is found that eigenbeamforming is the best choice for MIMO PLC: the full spatial diversity gain is achieved for highly attenuated channels and maximum multiplexing gain is achieved for channels with low attenuation by utilizing all spatial streams. It is shown that upgrading from a conventional single input single output (SISO) PLC configuration to a 2 by 2 MIMO configuration the throughput can be more than doubled while coverage is increased. The survey concludes with a review of specific MIMO PLC system implementations in the specifications ITU-T G.9963 and HomePlug AV2

A Review of Impedance Matching Techniques in Power Line Communications

“…MIMO (Multiple Input and Multiple Output) techniques have been heavily investigated and haven proven their advantages, e.g., increased capacity and communication reliability in wireless communications [112]. A PLC system's capacity increases when using MIMO techniques, as reported in Refs.…”

Power line communications (PLC) technology: More than 20 years of intense research

“…Some methods used to increase the performance of a communication system includes (i) increasing the bandwidth, (ii) applying an efficient coding technique, (iii) using bit and power loading, (iv) exploiting an adaptive scheduling, and (v) applying the MIMO transmission strategy. When using the MIMO strategy, a three‐wired (live, neutral, and protection earth) indoor PLC can be used in several combinations to form a MIMO‐PLC system . This gives the opportunity to treat the channel as a MIMO environment.…”

“…This gives the opportunity to treat the channel as a MIMO environment. In this respect, the channel transfer function is a QR matrix given by where R and Q are the numbers of input and output ports, respectively . The entries h ij represent the channel transfer function of the ( ij )th path, which is characterised by its ( ij )th front‐end gain.…”

Performance analysis on DPSK modulation using symbol repetition and interleaving

“…To improve the communication reliability of noncoherent systems, forward error correction such as Reed-Solomon and convolution code as stated in IEEE P1901.2 standard can be used. 14 Alternatively, the repetition scheme that repeatedly generates the same data for multiple times is also frequently used for low-power noncoherent system because of its simple decoding and encoding architecture. In fact, the repetition is widely used in various communication standards in spite of its loss in bandwidth.…”